Safety control means for explosively actuated tools



Feb. 23, 1960 R. J. KOPF ETAL SAFETY CONTROL MEANS FOR EXPLOSIVELY ACTUATED TOOLS Filed Aug. 28, 1956 livz 2 Sheets-Sheet 1 Feb. 23, 1960 R. J. KOPF ETAL SAFETY CONTROL MEANS FOR EXPLOSIVELY ACTUATED TOOLS Filed Aug. 28, 1956 2 Sheets-Sheet 2 FIGZ.

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United States Patent SAFETY CONTROL MEANS FOR EXPLOSIVELY ACTUATED TOOLS Rowland J. Kopf, Rocky River, Robert W. Henning, Fairview Park, and Roger Marsh, Hudson, Ohio, assignors, by mesne assignments, to Olin Mathieson Chemical Corporation, a corporation of Virginia Application August 28, 1956, Serial No. 606,639

7 Claims. (Cl. 1106) This invention relates to an improvement in a fastener driving tool, and more particularly to a safety device for a tool of the explosively-powered type, and is a continuation-in-part of our copending U.S. application, Serial No. 355,034, filed May 14, 1953.

In driving fasteners with tools of the type described in the aforementioned patent application, often it is desirable that the tool operator grasp the tool with two hands, for example, when special fixtures are attached to the barrel muzzle prior to driving a fastener through the fixture and into another member. However, it has been found that some operators fail to grasp the tool with both hands, particularly after driving a number of fasteners within a short period of time. By grasping the tool with two hands, the operator has far more control over the tool and is less likely to drop the tool when pressing it firmly against a work piece.

It is therefore an object of this invention to provide a safety device for fastener driving tools requiring the operator to properly grasp the tool with both hands in order to drive a fastener into a work piece.

Another object of this invention is to provide a novel device which may be easily and economically incorporated into existing tools of the type described in the aforementioned patent application to provide an additional safety feature.

Additional objects and advantages will be apparent from the following description and drawings in which:

Figure 1 is a perspective view of the subject tool inconporating an embodiment of the present invention;

Figure 2 is a schematic sectional view taken on the line 22 in Figure 1;

Figure 3 is a schematic sectional view taken on the line 33 in Figure 2;

Figure 4 is a schematic sectional view of a portion of Figure 2, but to an enlarged scale; and

Figure 5 is a schematic sectional view similar to Figure 1, but showing the tool in the operative fastener driving position.

The tool of the aforementioned patent application will be described to the extent necessary for a clear understanding of the structure, operation, and functioning of the safety device to which the present application is directed.

With reference to Figure 1, the tool 1 comprises a housing 3 including a front portion 5 and a rear portion 7. The front housing portion 5 provides a hand grip including finger positioning protrusions 6. The rear housing portion 7 provides a pistol grip including finger positioning protrusions 8. A shield 9 has projecting from the rear face thereof a shield tube 11 telescopically and nonrotatably mounted in the front housing member 5. A barrel 12 having a fastener receiving bore is telescopically mounted within the shield tube 11 and housing 3. The subject safety device includes an extension rod 13 telescopically and nonrotatably mounted in the housing. Both the shield tube 11, the barrel 12, and the extension rod 13 are constantly spring urged outwardly with respect 2,925,604 Patented Feb. 23, 1960 to the front housing member 5, as will be more fully described hereinafter. The rear housing member 7 is attached to the front housing member 5 by means of a pivotable connection 15, and the two housing members are locked together in the position shown in Figure 1 while driving a fastener. They are unlocked and sep arated to facilitate insertion of a fastener and an explosive cartridge into the breech end of the bore of barrel 12. The rear housing member 7 contains the firing mechanism including trigger 17. Neither the pivotablc connection 15 between the housing members 5 and 7, nor the firing means in any way affect the subject safety device, and a description of these features is therefore not necessary.

The operation of the tool described in the aforementioned patent application is as follows: With a fastener and cantridge properly positioned in the bore of barrel 12 the front and rear housing members are locked together i in the position shown in Figure 1. One of the safety features described in the aforementioned patent application requires that the shield 9 and barrel 12 be properly telescoped into the front housing member 5 from the position shown in Figures 1 and 2 to the position shown in Figure 5, in order to permit detonation of the cartridge to drive the fastener into a work piece W, against which the barrel muzzle and shield have been pressed. The purpose of this safety feature is to prevent discharge of a fastener from the muzzle end of the tool when the tool has not been properly pressed against the work piece. The tool described in the aforementioned patent application is provided with a second safety feature which may or may not be utilized at the discretion of the tool operator. This feature comprises an extension rod, similar to extension rod 13, telescopically received in the housing and spring urged outwardly in the direction of the shield. The extension rod is held retracted in the housing until the operator manually presses a button permitting the rod to be spring pressed outwardly against the shield. When the button is subsequently released, the rod is fixed in abutting relationship with the shield.

The subject invention is directed to a modification of the extension rod safety feature which adapts the rod to go automatically to a normally extended safety position. As set forth hereinafter, this is done by a structural arrangement which biases the rod and allows it to move to the extended position, but offers constraint to movement in the other direction unless the constraint is removed at the will of the operator. The arrangement involves first and second members comprising a tool housing and a barrel having a fastener ejecting bore. It also involves a third member mounted in the bore of one of the other members in a manner permitting the third member to move free in one direction in said bore, but only selectively in the other direction so .as to normally prevent movement of the tool parts into operative position, but to selectively allow movement to the operative position at the will of the tool operator manifested by the constant actuation of means for selectively releasing the third member. Unless the release means is main tained actuated by being gripped by the operator, the tool will not work.

With particular reference to Figure 2, the housing 5 is provided with a longitudinal bore 19 which telescopically receives the shield tube 11. A spring 21 engages a shoulder 23 near the breech end of the housing bore 19 and a shoulder 25 at the muzzle end of the shield tube 11, thus urging the shield 9 outwardly with respect to the housing 5. The tube shield is journaled in an inwardly.

directed boss 27 at the muzzle end of the housing 5. The boss 27 and the outer surface of the shield tube 11 have cooperating nonciroular configurations to prevent the shield from rotating with respect to the housing 5. It}

practice these configurations are hexagonal so that the shield can be removed from the housing and placed in a different position. So far as the subject safety device is concerned, the shield 9 and shield tube 11 may be rotatably mounted with respect to the housing 5. The barrel 12 is telescopically mounted within the shield tube 11 and within the housing bore 19. A boss 29 at the muzzle end of the shield tube 11 provides a journal for the muzzle end of the barrel 12 and another barrel journal 31 in the breech end of the housing bore 19 also provides the shoulder 23. A cap 33 is threaded onto the muzzle end of the barrel 12 and has a wider diameter than the internal diameter of the boss 29. Removal of the barrel 12 through the muule end of the tool must be prevented, and for purposes of illustration, a radially extending flange 35 fixed to the breech end of the barrell and engaging a counterbore 37 in the breech end of the housing member serves this function. To remove the shield 9 and the shield tube 11 from the housing 5, the cap 33 is unscrewed fro-m the muzzle end of the barrel 12 whereupon the spring 21 forces the shield outwardly and both the shield and spring may be removed. The barrel is removed through the breech end of the housing 5.

A second bore 39 is provided in the housing member 5, substantially parallel to the first bore 19. An extension rod or tube, as shown a tube, 13 is telescopically received in the bore 39 and is urged outwardly with respect to the muzzle end of the bore by a spring 41 which engages a plate 43 at the breech end of the bore 39 and a boss 45 extending radially inwardly intermediate the ends of the tube 13. A rod 47 is fixed to the plate 43 and extends partially through the bore 39 and through the boss 45 to prevent the tube 13 from jamming in the bore 39 and to maintain proper alignment of the spring 41. The plate 43 is held in place by a closure member 49 which is secured to the housing 5 by a bolt 51. The tube 13 passes through a bore or aperture 53 in a release button 55. The release button is slidably mounted in a socket 57 at the muzzle end of the housing 5. A compression spring 61 urges the button outwardly with respect to the socket 57 and the housing member 5. The extension tube 13 is threaded as at 62, on its outer surface with a buttress-type thread having an inclined face 63 and a face 65 substantially transverse to the longitudinal axis of the tube 13. The lower surface of the tube 13 has a flat surface 67. This flat surface engages the fiat sur-v face of a boss 69 extending inwardly from the bore 39, thus preventing rotation of the tube 13, with respect to the housing 5 or button 55. The fiat surface 67 stops just short of the breech end of the tube, providing a shoulder 71, which engages the'boss 69 to prevent removal of the tube forwardly through the bore 39. It is not necessary that the tube be nonrotatably mounted in the housing. The upper half of the aperture 53 of the release button 55 is provided with a similar cooperating thread 72 having an inclined face 73 and a face 75 substantially transverse to the longitudinal axis of the bore 53. The spring 41 is of sufficient force to maintain the muzzle end of the extension tube 13 in firm abutting relationship with the rear face of the shield 9. The release button 55 will be displaced inwardly by the coaction of the inclined faces 63 and 73 on the external wall 13 and the aperture wall 53 respectively during outward movement of the tube 13.

The threads 62 on the extension tube 13 and the thread 72 in aperture 53 in the release button 55 must have a configuration which will permit movement of the extension tube 13 outwardly with respect to the muzzle end of the bore 39 when the release button is in the locking position as shown in Figure 2. In addition, the threads must be such as to prevent telescopic movement of the extension tube 13 into the bore 3-9. Any type of thread which meets these requirements will serve adequately in place of the threads 62 and 72 shown in Figure 4.' The extension tube 13 and aperture 53 need not necessarily be provided with threads, but rather mating serrations of any type which will adequately fulfill the reqiurement outlined above are satisfactory.

It is not necessary that the extension tube 13 abut against a shield as 9, and any laterally projecting abutment member will sufiice.

The operation of the safety device is as follows: After the fastener and cartridge have been properly loaded into the barrel 12 and the housing members 5 and 7 properly closed and locked with respect to each other, the operator grasps the pistol grip portion of the rear housing member 7 in one hand and the front housing portion 5 in the other hand. The tool will be in the position shown in the Figures 1 and 2. The operator will be prevented from firing the tool without first pressing it against the work surface W, because the tube 11 of shield 9 and the barrel 12 have not been properly telescoped into the housing member 5. Should the operator now press the muzzle end of the tool against the work piece the housing 5 will not telescope over the tube 11 of shield 9 and barrel 12 because of the extension tube 13. The housing 5 cannot telescope forwardly to permit further entry of tube 13 into the bore 39 until the release button 55 has been depressed releasing the threaded faces 65 and 75 on the extension tube 13 and the release button aperture 53, respectively. Upon depressing the release button 55, the parts may be properly telescoped with respect to each other by pressing the housing 5 forwardly with the shield 9 and barrel 12 against the work surface W, to the position shown in Figure 5.

The functioning of the extension tube 13 differs from that of the extension rod described in the aforementioned patent application in that the previous tube was prevented from moving either inwardly or outwardly with respect to the housing until the release button was pressed. In the subject safety device, the extension tube 13 is constantly displaced forwardly or outwardly with respect to the muzzle end of the bore 39 and into abutting relationship with the shield 9. Should the shield 9 be removed from the tool, the extension tube 13 will move outwardly until the shoulder 71 engages the boss 69.

Therefore, in using the tool it is necessary that the operator grasp the tool with both hands, one hand around the pistol grip on housing portion 7 and the other hand around the housing portion 5, and that he further depresses the release button 55 and continue to hold it while pressing the tool against the work.

It is to be understood that the description and drawings are intended only to illustrate the subject safety device and incorporate only so much of the structure of the tool described in the aforementioned patent application as is necessary for a clear understanding of the safety device. The drawings are schematic and omissions and various changes have been effected to simplify the description and drawings, such as the barrel flange 35 and counterbore 37 in housing 5. Certain component parts have been shown as integral members whereas they may in the actual tool comprise several separate parts, as disclosed in the aforementioned patent application.

Although this invention has been described with respect to a preferred embodiment and certain details, various other embodiments and modifications will be apparent to one skilled in the art, and the invention is therefore not to be limited to such embodiments and details except as set forth in the appended claims.

We claim:

1. An explosive actuated fastener driving tool comprising a first member forming a housing and a second member forming a barrel for ejection of said fastener, said first member having a bore for mounting said members for telescopic movement with respect to each other between an outward safety position and an inward ready to-drive position, one of said members having a secondary bore, means telescopically mounting a third member in said secondary bore manually movable means carried on said one of said first two members for permitting free outward telescopic movement of said third member and normally urged to prevent relative inward telescopic movement between said member having said secondary bore and said third member unless said means is manually held out of said normal movement-preventing relationship, and abutment means on the other of said first two members operatively engageable with said third member to prevent inward telescopic movement of said first and second members to said ready-t -drive position when said member having said secondary bore is selectively prevented from moving with respect to said third member by said manually movable means.

2. In :a manually operable fastener driving tool or the like, a barrel through which a fastener is driven by a propellant fluid and a tool housing member having a handle portion adapted to be gripped by one hand of the tool operator, said barrel being mounted in said housing member, said housing member having limited telescopic movement with respect to said barrel and manually releasable means continually biased to stop telescopic movement of said member unless said means is continuously held released by the other hand of the tool operator.

3. In a fastener driving tool or the like having a barrel telescopically received in a housing and normally urged outwardly with respect to said housing, a member telescopically received in a bore in said housing and constantly urged outwardly with respect to said housing, releasable means to stop relative inward telescopic movement between said member and said housing when said means is released, and means inter-connecting said barrel and said member to stop said barrel and said housing from telescoping together when said member and said housing are stopped from telescoping together.

4. In the fastener driving tool or the like of claim 3, the last said means comprising means against which said member is constantly urged.

5. In a fastener driving tool or the like, a housing having a pair of substantially parallel bores, a tube telescopically mounted in one of said bores, a laterally extending shield mounted on an outer end of said tube, a barrel telescopically received in said tube and said housing and projecting outwardly from said housing, said housing being movable forwardly to an operative position, said housing being biased out of said operative position rearwardly with respect to said tube and barrel, an elongated member telescopically mounted in the second of said bores in said housing and a sear-like member slidably mounted in said housing in a bore transverse to and intersecting said second bore, said elongated member projecting through an aperture in said sear-like member, cooperating means on said sear-like member and said elongated member to permit rearward telescopic movement of said housing with respect to said elongated member and to prevent forward telescopic movement of said housing with respect to said elongated member when said sear-like member is in a first locking position and to permit said forward telescopic movement of said housing with respect to said elongated member when said searlike member is in a second releasing position, means normally urging said sear-like member into said first position, and said shield on said tube and said elongated member comprising cooperating means to stop telescopic move ment of said housing with respect to said tube when said housing is prevented from telescoping with respect to said elongated member, whereby said housing cannot be telescoped with respect to said barrel into said operative position until said sear is in said second position.

6. The tool of claim 5 wherein said second bore is open at both ends, a guide rod projecting into said bore and having a transverse flange at one end rigidly held against said housing adjacent said bore by a block, means for detachably mounting said block on said housing, a tube telescopically received in said bore to form said elongated member and telescopically receiving said rod, and biasing means engaging said tube and said flange to normally urge said tube outwardly with respect to said housing.

7. The article of claim 5 wherein the bore transverse to and intersecting the second bore is open .at an end and wherein the sear-like member is a release button telescopically received in said transverse bore and normally urged outwardly with respect to said open end to the locking position, said release button telescopically receiving the elongated member in the aperture, and wherein the cooperating means includes a buttress thread on said elongated member and said release button aperture, said release button in its locking position being urged against said elongated member to prevent forward telescopic movement of said housing while permitting forward telescopic movement of said elongated member, said button being moveable inwardly to the release position.

References Cited in the file of this patent UNITED STATES PATENTS 1,365,869 Temple Jan. 18, 1921 1,365,870 Temple Jan. 18, 1921 2,316,112 Temple Apr. 6, 1943 2,380,785 Percoco July 31, 1945 2,549,993 Temple Apr. 24, 1951 2,593,506 Wales Apr. 22, 1952 2,729,418 Maynard Ian. 3, 1956 FOREIGN PATENTS 708,692 Great Britain May 5, 1954 

